Although there are many reasons for buying a computer, one common reason at the moment is that Windows 10 will no longer be supported by Microsoft after October. Many computers that are running Windows 10 at the moment don’t meet the hardware requirements for Windows 11 which effectively means the need to be replaced. (Or they could be recycled by running Linux instead of Windows).
If you need a computer that can run Windows 11, I would recommend getting a second hand one as it will be much cheaper. I have bought some already on eBay and they are available for purchase at around £100 a laptop. At the moment the ones I have are all Lenovo and include X280 and L480.
Alternatively if you just need a computer and don’t actually need Windows then it should be possible to get a computer running Linux for around £50.